“For every four pitchers you draft,” the Padres’ senior adviser said this week, “two will break down.”

Even in this age of reduced offense, the quest to find a top-flight starting pitcher remains arguably the game’s top challenge. Because the number of arm injuries shows little sign of abating. Because the ever-improving field of statistical analysis gives teams more and more insight on mound opponents.

You wouldn’t know of such tough odds, though, if your introduction to baseball came in this Mets-Dodgers National League Division Series, which starts Friday at Dodger Stadium. The Mets’ long-awaited return to postseason baseball will be all about the high-achieving, high-ceiling arms: The Dodgers veteran, still-in-their-prime aces Clayton Kershaw and Zack Greinke starting Games 1 and 2 and the Mets’ young guns Jacob deGrom, Noah Syndergaard and Matt Harvey — though, for accuracy’s sake, deGrom is just three months younger than Kershaw — going in Games 1 through 3.

Get ready for a week of bicoastal power and precision on the mound. Of clinics on how to reach this peak and stay there.

“It’s really exciting to see how this group of young pitchers evolves around the playoffs,” said Hall of Fame hurler Pedro Martinez, who will work in the TBS studio for pregame and postgame.

Both teams could use even more, actually. Mets rookie left-hander Steven Matz, who impressed in limited action this season, has been shelved recently by back problems, and his availability for this round was in doubt as the Mets prepared. And the Dodgers’ rotation depth is so suspect they might turn to Kershaw to start Game 4 on three days’ rest.

Yet the paths taken by this series’ fab five indicate just how difficult it can be to find and cultivate a frontline starting pitcher. Consider…

Greinke, the oldest of this group (he turns 32 this month) was selected sixth overall by the Royals in the 2002 draft. Pretty high, right? Yet four pitchers were drafted ahead of him, including right-hander Bryan Bullington first overall by Pittsburgh, and none put together a big-league career of any substance.

The Dodgers, whose draft was overseen by White at the time, popped Kershaw seventh overall in 2006. Five pitchers went ahead; the only one of that five with a noteworthy career is Yankees closer Andrew Miller. Shortly behind Kershaw, the Giants took Tim Lincecum 10th, and the Diamondbacks chose Max Scherzer 11th.

Harvey and deGrom went in the same Mets draft of 2010. Three pitchers, none of whom have made an impact in the major leagues, went ahead of Harvey at No. 7 overall. Then 134 more pitchers learned of their fate, including 38th overall selection Syndergaard by Toronto, before deGrom went to the Mets in the ninth round.

“I just think it’s the way it goes,” said Miller, who faltered as a starting pitcher with Detroit, Florida and Boston before becoming a dominant reliever. “It’s not easy to find your way to succeed at this level. Not everybody ends up doing it.

“I think the hardest thing is sticking and finding a way to stay. There were a handful of superstars that came out of that [2006] first round. I think those are the outliers. Everybody else has got to do everything they can to find a way.”

So how do you find the guy who finds a way to not only stay, but stand out? It’s not a secret as much as a mix of factors internal and external. The diminutive Martinez, who received an opportunity with the Dodgers out of the Dominican Republic mostly because his older brother Ramon excelled for them, said, “All you have to do is command the strike zone. If you can command both sides of the plate, you can get guys out.”

Zack Greinke with the Royals in 2004AP

Allard Baird, the Royals’ general manager in 2002, had a similar idea in mind when he chose Greinke out of Apopka High School in Florida. “Our scouts did a good job of identifying his ability to pitch,” said Baird, who is now a senior vice president for the Red Sox. “It was very unique for a high school kid to have such advanced pitch ability. That’s usually a random happening for a high school kid.”

Four years later, White assumed even greater liability in going with Kershaw out of Highland Park High School in Texas.

“A lot of people were saying that high school left-handed pitchers are a risk,” White said. “But when you take elite players out of high school, like Clayton or [Matt] Kemp, [James] Loney, they get there quicker. Clayton, he got a lot better from the instruction [in the Dodgers’ minor leagues]. He’s a great competitor, a strong person. An absolute warrior.”

Omar Minaya, the Mets’ general manager from 2004 to 2010 and now an executive with the Major League Baseball Players Association, said, “When those guys get drafted with the top-10 picks, those guys are difference-makers. If you get picked in the second round, or in the compensation round — especially high-school guys — you can’t say those guys are difference-makers. Because if they were, they would’ve gone in the first round.”

That doesn’t guarantee success for that top tier, though. Of those three pitchers selected before Harvey in 2010 — Jameson Taillon by Pittsburgh, Drew Pomeranz by Cleveland and Barrett Loux by Arizona — only Pomeranz has even appeared in the major leagues.

“We’ve all been there. This business is an imperfect science,” Minaya said. “Guys may have the ability, guys may throw hard, but you don’t really know what’s inside a guy. It takes a little bit of luck.”

Speaking of which, Minaya said he doesn’t recall so much as meeting deGrom, because he was drafted so low.

“I credit the front office of the Mets, Paul [DePodesta] and Sandy [Alderson],” Minaya said. “[DeGrom’s] athlete component was identified, but he was a product of the development people.”

There’s no set path, clearly, to the top. It’s a grind of a path, though, which is why Kershaw and Greinke get paid so well and why the Mets’ guys will, too, if they keep trending upward.

The other reward — showcasing your talents on the largest platform — comes now. And those of us watching this series will be the biggest beneficiaries.